Got it working… didn’t do anything new. Still have the same error messages as above.

Despite having the phone Settings > Developer Options > Select USB Configuration set to "MTP (Media Transfer Protocol)… I noticed that when the USB cable was attached to phone there was an “Android System” box with a “N” logo I could tap for options. It still defaulted to “Charge this device”. Simply selected “Transfer files” and waited about 5 seconds.

The phone was then browseable by GNOME NEMO. A folder “Internal shared storage” appeared.